feat(images): Cloudflare Workers AI image provider (commit 1a)

First commit of the image + Instagram A/B pipeline workstream. Ships the Cloudflare Workers AI image provider, its pricing + validator helpers, four new settings fields in a new "Images" admin section, and unit tests with mocked HTTP. Nothing calls the provider yet from the article pipeline — integration lands in commit 1b. Why: CEO-approved on 2026-04-15 (see convo/prautoblogger/threads/2026-04-image-pipeline/01-cto-handoff.md). Style is locked to the 90s infomercial pastiche; default model is FLUX.1 [schnell] at ~$0.0011/MP (~$0.01/article for 8 images across 4 placements x 2 variants). Risk flags: - Direct call to Cloudflare Workers AI bypassing AI Gateway (decision D-001, documented in convo/prautoblogger/decisions/). Gateway route to Workers AI currently 403s; OpenRouter gateway path unaffected. - prab_event_log structured writes deferred to commit 1b when the table lands (decision D-002). Logger-based logging is in place now. - No schema changes. No existing code paths touched outside settings. - Backward compatible: provider is instantiable but not wired to any consumer yet. Test plan: - CI runs PHPUnit including the new CloudflareImageProviderTest. - After merge: verify the new Images section appears on the settings page, the style-suffix textarea pre-fills with the infomercial prompt, and entering the existing CLOUDFLARE_AI_TOKEN + account UUID lets a future "Test Connection" button return OK (button ships in a later commit; the underlying validate_credentials_detailed() works today). Files: - includes/providers/interface-image-provider.php (adopted from CTO draft) - includes/providers/class-cloudflare-image-provider.php (283 lines) - includes/providers/class-cloudflare-image-pricing.php (78 lines) - includes/providers/class-cloudflare-image-validator.php (107 lines) - includes/admin/class-settings-fields.php (+ Images section, 4 fields) - prautoblogger.php (+ PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL, _STYLE_SUFFIX) - tests/unit/Providers/CloudflareImageProviderTest.php - ARCHITECTURE.md (file tree, integrations table, options table, decision #16) - CONVENTIONS.md (How To: Add a New Image Provider) - CHANGELOG.md (Unreleased section) Agent-Session: cowork-2026-04-15-image-pipeline-commit-1a
2026-04-15 10:11:10 +07:00
parent 018a78000c
commit 11108b3bb5
10 changed files with 973 additions and 0 deletions
--- a/ARCHITECTURE.md
+++ b/ARCHITECTURE.md
@@ -132,6 +132,10 @@ prautoblogger/
 │   │   ├── interface-source-provider.php # Contract for any social media source
 │   │   ├── class-reddit-json-client.php  # Reddit HTTP client — RSS (primary) + .json (fallback)
 │   │   ├── class-reddit-provider.php     # Reddit data collection orchestrator (RSS primary)
 │   │   ├── interface-image-provider.php  # Contract for any image generation provider
 │   │   ├── class-cloudflare-image-provider.php # FLUX.1 via Cloudflare Workers AI
 │   │   ├── class-cloudflare-image-pricing.php  # Model alias + per-MP cost estimation
 │   │   ├── class-cloudflare-image-validator.php # Non-destructive credential + connectivity check
 │   │   └── (new providers go here — see CONVENTIONS.md)
 │   │
 │   ├── frontend/
@@ -338,6 +342,10 @@ All prefixed with `prautoblogger_`:
 | `prautoblogger_log_level`              | Logging threshold: error/warning/info/debug           |
 | `prautoblogger_db_version`             | Schema version for migrations                         |
 | `prautoblogger_schedule_time`          | Daily generation time (HH:MM, default: '03:00')       |
 | `prautoblogger_cloudflare_ai_token`    | Encrypted Cloudflare Workers AI API token             |
 | `prautoblogger_cloudflare_account_id`  | Cloudflare account UUID (plaintext — identifier, not secret) |
 | `prautoblogger_image_model`            | Image model alias: `flux-1-schnell` (default) or `flux-1-dev` |
 | `prautoblogger_image_style_suffix`     | Text appended to every image prompt (default: CEO-locked 90s infomercial prompt) |
 ### Post Meta
@@ -368,6 +376,7 @@ Stored on every PRAutoBlogger-generated post:
 | Reddit RSS | Primary Reddit data source — Atom feeds for subreddit hot posts | None (unauthenticated) | No known rate limit; reliable from datacenter IPs | `providers/class-reddit-json-client.php` |
 | Reddit .json | Fallback for posts + only source for comments | None (unauthenticated) | ~10 req/min (datacenter IPs often blocked) | `providers/class-reddit-json-client.php` |
 | Google Analytics 4 | Post performance metrics | OAuth2 service account | Standard GA4 limits | `core/class-ga4-client.php`, `core/class-metrics-collector.php` |
 | Cloudflare Workers AI | Image generation (FLUX.1 schnell / dev) for article hero, thumbnail, and IG placements | API token (encrypted in wp_options) + account ID | Workers AI per-account quotas | `providers/class-cloudflare-image-provider.php`, `providers/class-cloudflare-image-pricing.php`, `providers/class-cloudflare-image-validator.php` |
 ---
@@ -415,6 +424,9 @@ Each pipeline execution generates a UUID (`run_id`) that tags every `prab_genera
 ### #14: Reddit RSS replaces PullPush.io (and earlier Reddit OAuth)
 Reddit rejected our OAuth API application (April 2026). We initially switched to PullPush.io, but its index was frequently stale or unavailable. Reddit's RSS/Atom feeds (`/r/{sub}/hot.rss`) proved the most reliable option — they work from datacenter IPs where .json gets 403, require no auth, and have no apparent rate limit. The .json endpoints are kept as a fallback for posts and as the sole source for comment data. Each collected item's metadata includes a `data_source` field (`reddit_rss` or `reddit_json`) for auditability.
 ### #16: Image generation via Cloudflare Workers AI (FLUX.1), direct (not via AI Gateway)
 The image-generation layer (started 2026-04-15, tracked in `convo/prautoblogger/threads/2026-04-image-pipeline/`) uses FLUX.1 [schnell] on Cloudflare Workers AI as its default model, chosen for its ~$0.0011/MP cost and 2–3 sec latency. FLUX.1 [dev] is a ~4× cost upgrade exposed as a dropdown for specific posts that warrant it. Calls go directly to `https://api.cloudflare.com/client/v4/accounts/{id}/ai/run/@cf/black-forest-labs/...`, *not* through the Cloudflare AI Gateway that we use for OpenRouter — the gateway route to Workers AI currently 403s (pre-existing open issue). The provider lives behind `PRAutoBlogger_Image_Provider_Interface`, so the decision is trivially reversible: switching to a different image API (DALL-E, Replicate, a future AI Gateway route) is a new class implementation plus a one-line swap in the pipeline wiring. Trade-off: we run two different Cloudflare integration paths (gateway for OpenRouter LLMs, direct for Workers AI images) until the gateway route stabilizes — minor cognitive overhead, zero functional downside.
 ### #15: Optional Cloudflare AI Gateway in front of OpenRouter
 We already use Cloudflare for DNS/CDN on peptiderepo.com, so layering AI Gateway in front of OpenRouter is zero marginal infrastructure. It gives us response caching (meaningful for repeated classification/scoring calls), a unified cost/latency dashboard, rate limiting, and provider fallback — all of which we would otherwise have to build ourselves to satisfy the CTO cost-tracking rules. Kept as an opt-in URL setting (`prautoblogger_ai_gateway_base_url`) so the plugin still works unchanged out of the box and can be bypassed instantly if the gateway misbehaves. The gateway is a transparent OpenRouter-compatible proxy; no new provider class is needed, and the response parsing path (`usage`, `choices[0].message.content`) is unchanged.
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,38 @@ All notable changes to PRAutoBlogger will be documented in this file.
 Format follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project uses [Semantic Versioning](https://semver.org/).
 ## [Unreleased]
 ### Added
 - **Image provider: Cloudflare Workers AI (FLUX.1 family).** First commit of
  the image + Instagram A/B pipeline workstream. Ships the provider, its
  pricing + validator helpers, four new settings fields in a new "Images"
  admin section, and unit tests with mocked HTTP. Nothing calls the provider
  yet from the article pipeline — integration lands in commit 1b.
  - `includes/providers/interface-image-provider.php` (adopted from the CTO's
    uncommitted draft) — contract for any image provider.
  - `includes/providers/class-cloudflare-image-provider.php` — FLUX on Workers
    AI, direct call to `/accounts/{id}/ai/run/...` (bypassing AI Gateway per
    decision D-001); exponential-backoff retries on 429 / 5xx / network,
    loud fail on 4xx; handles both raw-bytes and JSON-envelope response shapes.
  - `includes/providers/class-cloudflare-image-pricing.php` — model alias →
    full Workers AI id resolution + per-megapixel cost estimation.
  - `includes/providers/class-cloudflare-image-validator.php` — non-destructive
    "Test Connection" credential check that never generates a real image.
  - Settings: `prautoblogger_cloudflare_ai_token` (encrypted),
    `prautoblogger_cloudflare_account_id`, `prautoblogger_image_model`
    (schnell / dev), `prautoblogger_image_style_suffix` (default = CEO-locked
    90s infomercial prompt).
  - Constants: `PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL`,
    `PRAUTOBLOGGER_DEFAULT_IMAGE_STYLE_SUFFIX`.
  - Tests: `tests/unit/Providers/CloudflareImageProviderTest.php` covers
    happy path (raw bytes + JSON envelope), dimension + empty-prompt
    validation, 4xx loud-fail without retry, unexpected response shape,
    cost scaling across models and dimensions, and missing-token diagnostics.
 - ARCHITECTURE.md: new key decision #16 (image pipeline: Cloudflare Workers
  AI), new external API integration row, new options rows, file tree updates.
 - CONVENTIONS.md: new "How To: Add a New Image Provider" section.
 ## [0.2.2] — 2026-04-12
 ### Changed
--- a/CONVENTIONS.md
+++ b/CONVENTIONS.md
@@ -122,6 +122,34 @@ interface PRAutoBlogger_Source_Provider_Interface {
 ---
 ## How To: Add a New Image Provider
 1. Create `includes/providers/class-{name}-image-provider.php`
 2. Implement `PRAutoBlogger_Image_Provider_Interface` (see `interface-image-provider.php`)
 3. Required methods: `generate_image()`, `estimate_cost()`, `get_provider_name()`, `validate_credentials_detailed()`
 4. Split helpers into companions if you'd exceed the 300-line cap. The Cloudflare provider splits into provider + pricing + validator — mirror that shape.
 5. Add API credentials fields to `admin/class-settings-fields.php` under the `prautoblogger_images` section
 6. Register the provider in `class-prautoblogger.php` loader once the image pipeline lands (commit 1b of the image workstream)
 7. Update `ARCHITECTURE.md` file tree, external API integrations table, and the options table
 ### Interface contract:
 ```php
 interface PRAutoBlogger_Image_Provider_Interface {
    public function generate_image( string $prompt, int $width, int $height, array $options = [] ): array; // {bytes, mime_type, width, height, model, seed, cost_usd, latency_ms}
    public function estimate_cost( int $width, int $height, array $options = [] ): float;
    public function get_provider_name(): string;                                   // e.g., 'cloudflare_workers_ai'
    public function validate_credentials_detailed(): array;                         // {status, message, debug?}
 }
 ```
 ### Retry + cost rules (non-negotiable)
 - 5xx / 429 / network errors: retry with exponential backoff up to `PRAUTOBLOGGER_MAX_RETRIES`, respect `Retry-After` when present.
 - 4xx other than 429: fail loudly on the first response — never retry a deterministic bad request.
 - Validation check must be non-destructive (no image generation).
 - Every attempt logs via `PRAutoBlogger_Logger` with context `{provider-slug}-image`.
 ---
 ## How To: Add a New Admin Setting
 1. Define the option key in the settings array in `admin/class-admin-page.php` → `get_settings_fields()` method
--- a/includes/admin/class-settings-fields.php
+++ b/includes/admin/class-settings-fields.php
@@ -57,6 +57,11 @@ class PRAutoBlogger_Settings_Fields {
 				'icon'        => 'dashicons-chart-area',
 				'description' => __( 'Connect Google Analytics 4 for post performance scoring.', 'prautoblogger' ),
 			],
 			'prautoblogger_images' => [
 				'title'       => __( 'Images', 'prautoblogger' ),
 				'icon'        => 'dashicons-format-image',
 				'description' => __( 'Cloudflare Workers AI credentials and image style controls.', 'prautoblogger' ),
 			],
 		];
 	}
@@ -329,6 +334,45 @@ class PRAutoBlogger_Settings_Fields {
 				'section'     => 'prautoblogger_analytics',
 				'description' => __( 'Paste the full JSON key file for a service account with Analytics read access.', 'prautoblogger' ),
 			],
 			// ── Images ─────────────────────────────────────────────────
 			[
 				'id'          => 'prautoblogger_cloudflare_ai_token',
 				'label'       => __( 'Cloudflare API Token', 'prautoblogger' ),
 				'type'        => 'password',
 				'section'     => 'prautoblogger_images',
 				'description' => __( 'Workers AI token with Read + Edit scope. Create at dash.cloudflare.com → AI → API Tokens.', 'prautoblogger' ),
 				'icon'        => '🔑',
 			],
 			[
 				'id'          => 'prautoblogger_cloudflare_account_id',
 				'label'       => __( 'Cloudflare Account ID', 'prautoblogger' ),
 				'type'        => 'text',
 				'section'     => 'prautoblogger_images',
 				'default'     => '',
 				'description' => __( 'The Account ID shown on your Cloudflare dashboard sidebar. Used to build the Workers AI URL.', 'prautoblogger' ),
 			],
 			[
 				'id'          => 'prautoblogger_image_model',
 				'label'       => __( 'Image Model', 'prautoblogger' ),
 				'type'        => 'select',
 				'section'     => 'prautoblogger_images',
 				'default'     => PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL,
 				'options'     => [
 					'flux-1-schnell' => __( 'FLUX.1 [schnell] — fast + cheap (default)', 'prautoblogger' ),
 					'flux-1-dev'     => __( 'FLUX.1 [dev] — higher quality, ~4× cost', 'prautoblogger' ),
 				],
 				'description' => __( 'Schnell is the normal choice. Only switch to [dev] when a specific post needs higher quality.', 'prautoblogger' ),
 				'badge'       => __( 'Low cost', 'prautoblogger' ),
 			],
 			[
 				'id'          => 'prautoblogger_image_style_suffix',
 				'label'       => __( 'Style Suffix', 'prautoblogger' ),
 				'type'        => 'textarea',
 				'section'     => 'prautoblogger_images',
 				'default'     => PRAUTOBLOGGER_DEFAULT_IMAGE_STYLE_SUFFIX,
 				'description' => __( 'Appended to every image prompt. Controls the visual look across all placements. Changing this mid-run will cause visible style drift — prefer changing during quiet periods.', 'prautoblogger' ),
 			],
 		];
 	}
 }
--- a/includes/providers/class-cloudflare-image-pricing.php
+++ b/includes/providers/class-cloudflare-image-pricing.php
@@ -0,0 +1,78 @@
 <?php
 declare(strict_types=1);
 /**
 * Pricing + model-id resolution helpers for the Cloudflare image provider.
 *
 * Kept separate from the provider so the provider stays under the 300-line
 * cap and so cost estimation can be unit-tested without spinning up HTTP
 * mocks. Mirrors the `class-open-router-pricing.php` split.
 *
 * Triggered by: PRAutoBlogger_Cloudflare_Image_Provider (both generate_image()
 *               and estimate_cost() delegate here).
 * Dependencies: None — pure calculation + option reads.
 *
 * @see class-cloudflare-image-provider.php — Caller.
 * @see class-open-router-pricing.php       — Sibling pattern for LLM pricing.
 */
 class PRAutoBlogger_Cloudflare_Image_Pricing {
 	/**
 	 * Cloudflare Workers AI FLUX pricing (USD per megapixel), April 2026.
 	 * Single source of truth — update here if Cloudflare repricies.
 	 */
 	private const COST_PER_MP_SCHNELL_USD = 0.0011;
 	private const COST_MULTIPLIER_DEV     = 4.0;
 	/**
 	 * Short-alias → fully-qualified Workers AI model id.
 	 *
 	 * @var array<string, string>
 	 */
 	private const MODEL_ALIAS_MAP = [
 		'flux-1-schnell' => '@cf/black-forest-labs/flux-1-schnell',
 		'flux-1-dev'     => '@cf/black-forest-labs/flux-1-dev',
 	];
 	/**
 	 * Normalize a caller's model hint to a fully-qualified Workers AI id.
 	 *
 	 * Accepts short aliases (`flux-1-schnell`), fully-qualified names
 	 * (`@cf/black-forest-labs/...`), or empty. Empty input falls back to
 	 * the site option, then to the hardcoded default.
 	 *
 	 * @param string $hint Caller-supplied model identifier (may be empty).
 	 * @return string Fully-qualified Workers AI model id suitable for the URL path.
 	 */
 	public function resolve_model( string $hint ): string {
 		$hint = trim( $hint );
 		if ( '' === $hint ) {
 			$hint = (string) get_option( 'prautoblogger_image_model', PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL );
 		}
 		if ( 0 === strpos( $hint, '@cf/' ) ) {
 			return $hint;
 		}
 		return self::MODEL_ALIAS_MAP[ $hint ] ?? self::MODEL_ALIAS_MAP['flux-1-schnell'];
 	}
 	/**
 	 * Estimate USD cost for a single image at the given dimensions.
 	 *
 	 * FLUX is priced per megapixel of output. Schnell is the baseline;
 	 * [dev] is a ~4x multiplier. We clamp the MP floor at 0.01 so a
 	 * tiny thumbnail doesn't round to zero and bypass the budget check.
 	 *
 	 * @param int    $width  Width in pixels.
 	 * @param int    $height Height in pixels.
 	 * @param string $model  Fully-qualified Workers AI model id (call resolve_model first).
 	 * @return float USD cost rounded to 6 decimals.
 	 */
 	public function estimate_cost( int $width, int $height, string $model ): float {
 		$mp   = max( 0.01, ( $width * $height ) / 1_000_000 );
 		$rate = self::COST_PER_MP_SCHNELL_USD;
 		if ( false !== strpos( $model, 'flux-1-dev' ) ) {
 			$rate *= self::COST_MULTIPLIER_DEV;
 		}
 		return round( $mp * $rate, 6 );
 	}
 }
--- a/includes/providers/class-cloudflare-image-provider.php
+++ b/includes/providers/class-cloudflare-image-provider.php
@@ -0,0 +1,284 @@
 <?php
 declare(strict_types=1);
 /**
 * Cloudflare Workers AI image provider — FLUX.1 family.
 *
 * Calls `https://api.cloudflare.com/client/v4/accounts/{id}/ai/run/{model}`
 * directly. We bypass the Cloudflare AI Gateway for v1 because the gateway
 * route to Workers AI currently 403s (see decision D-001); the OpenRouter
 * gateway path is unaffected.
 *
 * Triggered by: PRAutoBlogger_Image_Pipeline (commit 1b) during the content
 *               generation run, after editorial review, before publish. Also
 *               triggered by the admin "Test Connection" action.
 * Dependencies: PRAutoBlogger_Encryption (token decryption), PRAutoBlogger_Logger
 *               (WARN/ERROR lines), PRAutoBlogger_Cloudflare_Image_Pricing
 *               (model resolution + cost estimation).
 *
 * @see interface-image-provider.php           Interface this class implements.
 * @see class-cloudflare-image-pricing.php     Cost + model id helpers.
 * @see class-cloudflare-image-validator.php   Credential check helper.
 * @see class-open-router-provider.php         Sibling provider; same retry pattern.
 * @see ARCHITECTURE.md                        External API Integrations, key decision #16.
 */
 class PRAutoBlogger_Cloudflare_Image_Provider implements PRAutoBlogger_Image_Provider_Interface {
 	private const PROVIDER_ID           = 'cloudflare_workers_ai';
 	private const MIN_DIMENSION_PX      = 64;
 	private const MAX_DIMENSION_PX      = 2048;
 	private const DEFAULT_STEPS_SCHNELL = 4;
 	private const RETRY_AFTER_CAP_S     = 60;
 	/**
 	 * Pricing + model-id resolver. Constructed once per provider instance.
 	 *
 	 * @var PRAutoBlogger_Cloudflare_Image_Pricing
 	 */
 	private PRAutoBlogger_Cloudflare_Image_Pricing $pricing;
 	public function __construct() {
 		$this->pricing = new PRAutoBlogger_Cloudflare_Image_Pricing();
 	}
 	/**
 	 * Generate a single image from a prompt at the requested dimensions.
 	 *
 	 * Retries 5xx / 429 / network errors with exponential backoff bounded
 	 * by PRAUTOBLOGGER_MAX_RETRIES. 4xx other than 429 fail loudly on the
 	 * first attempt — retrying a bad prompt or a bad token wastes money.
 	 *
 	 * Side effects: one HTTP request per attempt; one Logger line per attempt.
 	 *
 	 * {@inheritDoc}
 	 *
 	 * @throws \InvalidArgumentException If dimensions out of range or prompt empty.
 	 * @throws \RuntimeException         On auth failure, bad response shape, or retry exhaustion.
 	 */
 	public function generate_image( string $prompt, int $width, int $height, array $options = [] ): array {
 		$this->assert_valid_dimensions( $width, $height );
 		$prompt = trim( $prompt );
 		if ( '' === $prompt ) {
 			throw new \InvalidArgumentException(
 				esc_html__( 'Image prompt cannot be empty.', 'prautoblogger' )
 			);
 		}
 		$account_id = $this->get_account_id();
 		$api_token  = $this->get_api_token();
 		$model      = $this->pricing->resolve_model( (string) ( $options['model'] ?? '' ) );
 		$body = [
 			'prompt' => $prompt,
 			'width'  => $width,
 			'height' => $height,
 			'steps'  => (int) ( $options['steps'] ?? self::DEFAULT_STEPS_SCHNELL ),
 		];
 		if ( isset( $options['seed'] ) ) {
 			$body['seed'] = (int) $options['seed'];
 		}
 		$url        = $this->build_endpoint_url( $account_id, $model );
 		$headers    = [
 			'Authorization' => 'Bearer ' . $api_token,
 			'Content-Type'  => 'application/json',
 			'Accept'        => 'image/*',
 		];
 		$started_at = microtime( true );
 		$last_error = '';
 		for ( $attempt = 1; $attempt <= PRAUTOBLOGGER_MAX_RETRIES; $attempt++ ) {
 			$response = wp_remote_post(
 				$url,
 				[
 					'timeout' => PRAUTOBLOGGER_API_TIMEOUT_SECONDS,
 					'headers' => $headers,
 					'body'    => wp_json_encode( $body ),
 				]
 			);
 			if ( is_wp_error( $response ) ) {
 				$last_error = $response->get_error_message();
 				$this->log_retryable_failure( $attempt, 'network', $last_error );
 				$this->sleep_for_attempt( $attempt );
 				continue;
 			}
 			$status = (int) wp_remote_retrieve_response_code( $response );
 			$raw    = (string) wp_remote_retrieve_body( $response );
 			if ( 429 === $status || $status >= 500 ) {
 				$last_error = sprintf( 'HTTP %d: %s', $status, substr( $raw, 0, 300 ) );
 				$this->log_retryable_failure( $attempt, (string) $status, $last_error );
 				if ( $attempt < PRAUTOBLOGGER_MAX_RETRIES ) {
 					$retry_after = (int) wp_remote_retrieve_header( $response, 'retry-after' );
 					$this->sleep_for_attempt( $attempt, $retry_after );
 				}
 				continue;
 			}
 			if ( $status >= 400 ) {
 				$this->log_client_error( $status, $api_token, $account_id, $raw );
 				throw new \RuntimeException(
 					sprintf(
 						/* translators: %1$d: HTTP status, %2$s: error body. */
 						esc_html__( 'Cloudflare Workers AI error (HTTP %1$d): %2$s', 'prautoblogger' ),
 						$status,
 						substr( $raw, 0, 300 )
 					)
 				);
 			}
 			// Success. FLUX on Workers AI returns either raw image bytes
 			// (Content-Type: image/*) or a JSON envelope with base64 under
 			// `result.image`. Handle both without branching the caller.
 			$mime           = (string) wp_remote_retrieve_header( $response, 'content-type' );
 			[ $raw, $mime ] = $this->normalize_response_body( $raw, $mime );
 			return [
 				'bytes'      => $raw,
 				'mime_type'  => $mime,
 				'width'      => $width,
 				'height'     => $height,
 				'model'      => $model,
 				'seed'       => isset( $body['seed'] ) ? (int) $body['seed'] : null,
 				'cost_usd'   => $this->pricing->estimate_cost( $width, $height, $model ),
 				'latency_ms' => (int) ( ( microtime( true ) - $started_at ) * 1000 ),
 			];
 		}
 		throw new \RuntimeException(
 			sprintf(
 				/* translators: %1$d: max retries, %2$s: last error. */
 				esc_html__( 'Cloudflare Workers AI failed after %1$d attempts. Last error: %2$s', 'prautoblogger' ),
 				PRAUTOBLOGGER_MAX_RETRIES,
 				$last_error
 			)
 		);
 	}
 	/**
 	 * Estimate the USD cost of a single generation call.
 	 *
 	 * {@inheritDoc}
 	 */
 	public function estimate_cost( int $width, int $height, array $options = [] ): float {
 		$model = $this->pricing->resolve_model( (string) ( $options['model'] ?? '' ) );
 		return $this->pricing->estimate_cost( $width, $height, $model );
 	}
 	/**
 	 * @return string Machine-readable provider id used in logs and settings.
 	 */
 	public function get_provider_name(): string {
 		return self::PROVIDER_ID;
 	}
 	/**
 	 * Verify credentials are present and the API is reachable.
 	 *
 	 * Delegates to PRAutoBlogger_Cloudflare_Image_Validator so the HTTP probe
 	 * and error-shape code can be tested and sized independently.
 	 *
 	 * Side effects: one HTTP GET via the validator; one Logger line on failure.
 	 *
 	 * @return array{status: string, message: string, debug?: string}
 	 */
 	public function validate_credentials_detailed(): array {
 		return ( new PRAutoBlogger_Cloudflare_Image_Validator() )->run();
 	}
 	/** Enforce the interface's dimension contract. */
 	private function assert_valid_dimensions( int $width, int $height ): void {
 		if (
 			$width < self::MIN_DIMENSION_PX || $width > self::MAX_DIMENSION_PX ||
 			$height < self::MIN_DIMENSION_PX || $height > self::MAX_DIMENSION_PX
 		) {
 			throw new \InvalidArgumentException(
 				sprintf(
 					/* translators: %1$d: width, %2$d: height, %3$d: min, %4$d: max. */
 					esc_html__( 'Image dimensions %1$dx%2$d are outside the supported range (%3$d–%4$d px per axis).', 'prautoblogger' ),
 					$width,
 					$height,
 					self::MIN_DIMENSION_PX,
 					self::MAX_DIMENSION_PX
 				)
 			);
 		}
 	}
 	/** Normalize a 2xx response into [bytes, mime-type] whether raw or JSON-wrapped. */
 	private function normalize_response_body( string $raw, string $mime ): array {
 		if ( '' !== $mime && 0 === stripos( $mime, 'image/' ) ) {
 			return [ $raw, $mime ];
 		}
 		$decoded = json_decode( $raw, true );
 		if ( is_array( $decoded ) && isset( $decoded['result']['image'] ) && is_string( $decoded['result']['image'] ) ) {
 			$bytes = (string) base64_decode( $decoded['result']['image'], true );
 			if ( '' !== $bytes ) {
 				return [ $bytes, 'image/png' ];
 			}
 		}
 		throw new \RuntimeException(
 			esc_html__( 'Cloudflare Workers AI returned an unexpected response shape.', 'prautoblogger' )
 		);
 	}
 	private function build_endpoint_url( string $account_id, string $model ): string {
 		return sprintf(
 			'https://api.cloudflare.com/client/v4/accounts/%s/ai/run/%s',
 			rawurlencode( $account_id ),
 			ltrim( $model, '/' )
 		);
 	}
 	private function get_api_token(): string {
 		$encrypted = (string) get_option( 'prautoblogger_cloudflare_ai_token', '' );
 		if ( '' === $encrypted ) {
 			return '';
 		}
 		return (string) PRAutoBlogger_Encryption::decrypt( $encrypted );
 	}
 	private function get_account_id(): string {
 		return trim( (string) get_option( 'prautoblogger_cloudflare_account_id', '' ) );
 	}
 	private function log_retryable_failure( int $attempt, string $failure_class, string $detail ): void {
 		PRAutoBlogger_Logger::instance()->warning(
 			sprintf(
 				'Cloudflare image gen %s failure (attempt %d/%d): %s',
 				$failure_class,
 				$attempt,
 				PRAUTOBLOGGER_MAX_RETRIES,
 				$detail
 			),
 			'cloudflare-image'
 		);
 	}
 	/** Log an unrecoverable 4xx with triage context (never the full secret). */
 	private function log_client_error( int $status, string $api_token, string $account_id, string $raw ): void {
 		PRAutoBlogger_Logger::instance()->error(
 			sprintf(
 				'Cloudflare image gen HTTP %d (token_prefix=%s, token_len=%d, account=%s): %s',
 				$status,
 				substr( $api_token, 0, 4 ),
 				strlen( $api_token ),
 				substr( $account_id, 0, 6 ),
 				substr( $raw, 0, 300 )
 			),
 			'cloudflare-image'
 		);
 	}
 	/** Sleep between retries; Retry-After header wins when present, else exponential backoff. */
 	private function sleep_for_attempt( int $attempt, int $retry_after_secs = 0 ): void {
 		$backoff = PRAUTOBLOGGER_RETRY_BASE_DELAY_SECONDS * (int) pow( 2, $attempt - 1 );
 		$delay   = $retry_after_secs > 0 ? min( $retry_after_secs, self::RETRY_AFTER_CAP_S ) : $backoff;
 		if ( $delay > 0 ) {
 			sleep( $delay );
 		}
 	}
 }
--- a/includes/providers/class-cloudflare-image-validator.php
+++ b/includes/providers/class-cloudflare-image-validator.php
@@ -0,0 +1,107 @@
 <?php
 declare(strict_types=1);
 /**
 * Credential + connectivity validator for the Cloudflare image provider.
 *
 * Split out of the provider to keep each file under the 300-line cap and
 * to keep the validation path easy to unit-test without spinning up the
 * retry loop. The provider's `validate_credentials_detailed()` delegates
 * straight to `run()` here.
 *
 * Triggered by: PRAutoBlogger_Cloudflare_Image_Provider::validate_credentials_detailed()
 *               which is called by the admin "Test Connection" action.
 * Dependencies: PRAutoBlogger_Encryption (token decryption), PRAutoBlogger_Logger
 *               (WARN/ERROR lines), wp_remote_get().
 *
 * @see class-cloudflare-image-provider.php Parent class that delegates here.
 * @see interface-image-provider.php        Return-shape contract.
 */
 class PRAutoBlogger_Cloudflare_Image_Validator {
 	private const TIMEOUT_SECONDS = 15;
 	/**
 	 * Run a non-destructive credential check.
 	 *
 	 * Lightweight probe: hits the account-scoped AI models listing endpoint.
 	 * Never generates a real image — that would cost money on every click.
 	 *
 	 * Side effects: one HTTP GET; one Logger line on failure.
 	 *
 	 * @return array{status: string, message: string, debug?: string}
 	 */
 	public function run(): array {
 		$account_id = trim( (string) get_option( 'prautoblogger_cloudflare_account_id', '' ) );
 		if ( '' === $account_id ) {
 			return $this->err(
 				'account_id_empty',
 				__( 'Cloudflare account ID is not set. Go to PRAutoBlogger → Settings → Images.', 'prautoblogger' )
 			);
 		}
 		$encrypted = (string) get_option( 'prautoblogger_cloudflare_ai_token', '' );
 		$api_token = '' === $encrypted ? '' : (string) PRAutoBlogger_Encryption::decrypt( $encrypted );
 		if ( '' === $api_token ) {
 			return $this->err(
 				'token_empty',
 				__( 'Cloudflare API token is not set. Go to PRAutoBlogger → Settings → Images.', 'prautoblogger' )
 			);
 		}
 		$response = wp_remote_get(
 			sprintf(
 				'https://api.cloudflare.com/client/v4/accounts/%s/ai/models/search?per_page=1',
 				rawurlencode( $account_id )
 			),
 			[
 				'timeout' => self::TIMEOUT_SECONDS,
 				'headers' => [
 					'Authorization' => 'Bearer ' . $api_token,
 					'Content-Type'  => 'application/json',
 				],
 			]
 		);
 		if ( is_wp_error( $response ) ) {
 			$msg = $response->get_error_message();
 			PRAutoBlogger_Logger::instance()->error(
 				sprintf( 'Cloudflare credential check wp_error: %s', $msg ),
 				'cloudflare-image'
 			);
 			return $this->err(
 				'wp_error:' . $msg,
 				sprintf( __( 'Network error reaching Cloudflare: %s', 'prautoblogger' ), $msg )
 			);
 		}
 		$status = (int) wp_remote_retrieve_response_code( $response );
 		if ( 200 === $status ) {
 			return [
 				'status'  => 'ok',
 				'message' => __( 'Cloudflare Workers AI connected.', 'prautoblogger' ),
 			];
 		}
 		$body = (string) wp_remote_retrieve_body( $response );
 		PRAutoBlogger_Logger::instance()->warning(
 			sprintf( 'Cloudflare credential check HTTP %d: %s', $status, substr( $body, 0, 200 ) ),
 			'cloudflare-image'
 		);
 		return $this->err(
 			sprintf( 'http_%d', $status ),
 			sprintf( __( 'Cloudflare returned HTTP %1$d. %2$s', 'prautoblogger' ), $status, substr( $body, 0, 200 ) )
 		);
 	}
 	/**
 	 * @return array{status: string, message: string, debug: string}
 	 */
 	private function err( string $debug, string $message ): array {
 		return [
 			'status'  => 'error',
 			'message' => $message,
 			'debug'   => $debug,
 		];
 	}
 }
--- a/includes/providers/interface-image-provider.php
+++ b/includes/providers/interface-image-provider.php
@@ -0,0 +1,100 @@
 <?php
 declare(strict_types=1);
 /**
 * Contract for any image generation provider (Cloudflare Workers AI, DALL-E, etc.).
 *
 * Consumers depend on this interface, never on a concrete provider — swapping
 * providers means writing one new class, not refactoring the pipeline. This
 * mirrors the LLM provider pattern in `interface-llm-provider.php` (see CTO
 * rule #7 — interface for external service integrations).
 *
 * Triggered by: PRAutoBlogger_Image_Pipeline (added in commit #1b) during the
 *               content generation run, after editorial review, before publish.
 * Dependencies: None at interface level — implementations wrap a specific HTTP API.
 *
 * @see class-cloudflare-image-provider.php — Default implementation (FLUX.1 via Workers AI).
 * @see interface-llm-provider.php          — Parallel pattern for LLM providers.
 * @see ARCHITECTURE.md                     — External API Integrations table.
 */
 interface PRAutoBlogger_Image_Provider_Interface {
 	/**
 	 * Generate a single image from a prompt at the requested dimensions.
 	 *
 	 * Implementations MUST:
 	 *   - Apply retry + exponential backoff on transient failures (5xx, network).
 	 *   - Fail loudly on client errors (4xx) rather than silently returning empty.
 	 *   - Log each attempt via PRAutoBlogger_Logger.
 	 *   - Persist a structured event row via PRAutoBlogger_Event_Log (added in a
 	 *     later commit — safe to no-op until then).
 	 *
 	 * Side effects: HTTP request to the provider API.
 	 *
 	 * @param string $prompt Full prompt (concept + style suffix already concatenated).
 	 * @param int    $width  Target width in pixels (>= 64, <= 2048).
 	 * @param int    $height Target height in pixels (>= 64, <= 2048).
 	 * @param array{
 	 *     seed?: int,
 	 *     steps?: int,
 	 *     model?: string,
 	 * } $options Optional tuning. `seed` lets the caller ask for visually
 	 *           coherent variants across placements. `steps` trades quality
 	 *           for cost (default model-dependent). `model` picks a specific
 	 *           model identifier; implementations may ignore values they
 	 *           don't support.
 	 *
 	 * @return array{
 	 *     bytes: string,
 	 *     mime_type: string,
 	 *     width: int,
 	 *     height: int,
 	 *     model: string,
 	 *     seed: ?int,
 	 *     cost_usd: float,
 	 *     latency_ms: int,
 	 * } Raw image bytes (PNG or JPEG) plus metadata. Metadata is used by the
 	 *   caller to write post meta and to bill against the plugin's cost budget.
 	 *
 	 * @throws \RuntimeException On API error after retries exhausted, or on
 	 *                            an invalid response shape.
 	 * @throws \InvalidArgumentException If dimensions are out of range.
 	 */
 	public function generate_image( string $prompt, int $width, int $height, array $options = [] ): array;
 	/**
 	 * Estimate the USD cost of a single generation call before making it.
 	 *
 	 * Used by the cost tracker to pre-check budget and to show an expected
 	 * spend figure in the dry-run preview.
 	 *
 	 * @param int   $width  Target width in pixels.
 	 * @param int   $height Target height in pixels.
 	 * @param array $options Same shape as generate_image() options.
 	 *
 	 * @return float Estimated cost in USD for a single image at the given dimensions.
 	 */
 	public function estimate_cost( int $width, int $height, array $options = [] ): float;
 	/**
 	 * Machine-readable provider identifier used in logs and settings.
 	 *
 	 * @return string Lowercase identifier, e.g. 'cloudflare_workers_ai'.
 	 */
 	public function get_provider_name(): string;
 	/**
 	 * Verify the provider credentials are present and the API is reachable.
 	 *
 	 * Used by the admin "Test Connections" action. Implementations should make
 	 * a lightweight request (e.g. a models list or token verify endpoint) — NOT
 	 * generate a real image.
 	 *
 	 * Side effects: HTTP request, logs the result.
 	 *
 	 * @return array{status: string, message: string, debug?: string}
 	 *         status is 'ok' or 'error'; message is human-readable for the
 	 *         admin UI; debug is optional diagnostic detail for logs.
 	 */
 	public function validate_credentials_detailed(): array;
 }
--- a/prautoblogger.php
+++ b/prautoblogger.php
@@ -53,6 +53,19 @@ define( 'PRAUTOBLOGGER_DEFAULT_ANALYSIS_MODEL', 'google/gemini-2.5-flash-lite' )
 define( 'PRAUTOBLOGGER_DEFAULT_WRITING_MODEL', 'google/gemini-2.5-flash-lite' );
 define( 'PRAUTOBLOGGER_DEFAULT_EDITOR_MODEL', 'google/gemini-2.5-flash-lite' );
 // Image generation defaults (Cloudflare Workers AI, FLUX family).
 // Short alias; the Cloudflare image pricing helper expands it to the full
 // `@cf/black-forest-labs/...` model id when building the Workers AI URL.
 define( 'PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL', 'flux-1-schnell' );
 // CEO-approved image style suffix (decision locked 2026-04-15). Users may
 // override via Settings → Images → Style Suffix; this constant is the
 // fallback the setting reads on first install.
 define(
 	'PRAUTOBLOGGER_DEFAULT_IMAGE_STYLE_SUFFIX',
 	'Style: a screengrab from a 1995 late-night cable TV infomercial, oversaturated warm colors, VHS tape noise and scan lines, a bright yellow starburst graphic in the top right corner reading NEW, cheap studio lighting, dated 4:3 television framing, deadpan earnest expression, faint lens distortion, tacky low-budget commercial aesthetic.'
 );
 /*
 |--------------------------------------------------------------------------
 | Autoloader
--- a/tests/unit/Providers/CloudflareImageProviderTest.php
+++ b/tests/unit/Providers/CloudflareImageProviderTest.php
@@ -0,0 +1,275 @@
 <?php
 /**
 * Tests for PRAutoBlogger_Cloudflare_Image_Provider.
 *
 * Validates the image provider interface implementation methods.
 * All HTTP calls are mocked — no real API calls.
 *
 * @package PRAutoBlogger\Tests\Providers
 */
 namespace PRAutoBlogger\Tests\Providers;
 use PRAutoBlogger\Tests\BaseTestCase;
 use Brain\Monkey\Functions;
 class CloudflareImageProviderTest extends BaseTestCase {
 	/**
 	 * Fake PNG payload — bytes don't need to be a real PNG, just non-empty.
 	 * Using a short string keeps failure messages readable.
 	 */
 	private const FAKE_IMAGE_BYTES = 'FAKE_PNG_BYTES';
 	protected function setUp(): void {
 		parent::setUp();
 		// PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL constant is defined in
 		// prautoblogger.php — define here for test isolation.
 		if ( ! defined( 'PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL' ) ) {
 			define( 'PRAUTOBLOGGER_DEFAULT_IMAGE_MODEL', 'flux-1-schnell' );
 		}
 		$this->stub_get_option( [
 			'prautoblogger_cloudflare_ai_token'  => '',
 			'prautoblogger_cloudflare_account_id' => 'test-account-uuid',
 			'prautoblogger_image_model'          => 'flux-1-schnell',
 			'prautoblogger_log_level'            => 'info',
 		] );
 		Functions\when( 'wp_salt' )->justReturn( 'test_salt_key_for_unit_tests' );
 		Functions\when( 'is_wp_error' )->justReturn( false );
 		Functions\when( 'wp_remote_retrieve_header' )->justReturn( '' );
 	}
 	/**
 	 * Helper: configure the plaintext API token the provider will eventually
 	 * see after decryption. We round-trip through the real Encryption class
 	 * (rather than stubbing it) so this test catches any regressions in the
 	 * encrypt → option → decrypt flow at the same time.
 	 */
 	private function with_token( string $plaintext ): void {
 		$ciphertext = \PRAutoBlogger_Encryption::encrypt( $plaintext );
 		$this->stub_get_option( [
 			'prautoblogger_cloudflare_ai_token'   => $ciphertext,
 			'prautoblogger_cloudflare_account_id' => 'test-account-uuid',
 			'prautoblogger_image_model'           => 'flux-1-schnell',
 			'prautoblogger_log_level'             => 'info',
 		] );
 	}
 	/**
 	 * Provider implements the interface.
 	 */
 	public function test_provider_implements_interface(): void {
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$this->assertInstanceOf( \PRAutoBlogger_Image_Provider_Interface::class, $provider );
 	}
 	/**
 	 * get_provider_name returns the stable machine identifier.
 	 */
 	public function test_provider_name_is_stable_identifier(): void {
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$this->assertSame( 'cloudflare_workers_ai', $provider->get_provider_name() );
 	}
 	/**
 	 * Dimension validation rejects inputs outside the [64, 2048] envelope
 	 * before any HTTP call is made.
 	 */
 	public function test_generate_image_rejects_out_of_range_dimensions(): void {
 		$this->with_token( 'test-token' );
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$this->expectException( \InvalidArgumentException::class );
 		$provider->generate_image( 'a prompt', 32, 1080 );
 	}
 	/**
 	 * Empty prompts are rejected — an empty string burns budget on
 	 * Workers AI for a deterministic "bad request" result.
 	 */
 	public function test_generate_image_rejects_empty_prompt(): void {
 		$this->with_token( 'test-token' );
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$this->expectException( \InvalidArgumentException::class );
 		$provider->generate_image( '   ', 1080, 1080 );
 	}
 	/**
 	 * Happy path — raw image bytes come back with expected metadata shape.
 	 */
 	public function test_generate_image_returns_raw_bytes_and_metadata(): void {
 		$this->with_token( 'test-token' );
 		Functions\when( 'wp_remote_post' )->justReturn( [
 			'body'     => self::FAKE_IMAGE_BYTES,
 			'response' => [ 'code' => 200 ],
 			'headers'  => [ 'content-type' => 'image/png' ],
 		] );
 		Functions\when( 'wp_remote_retrieve_response_code' )->justReturn( 200 );
 		Functions\when( 'wp_remote_retrieve_body' )->justReturn( self::FAKE_IMAGE_BYTES );
 		Functions\when( 'wp_remote_retrieve_header' )->alias(
 			function ( $_response, $name ) {
 				return 'content-type' === strtolower( (string) $name ) ? 'image/png' : '';
 			}
 		);
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$result   = $provider->generate_image( 'a prompt', 1080, 1080, [ 'seed' => 42 ] );
 		$this->assertSame( self::FAKE_IMAGE_BYTES, $result['bytes'] );
 		$this->assertSame( 'image/png', $result['mime_type'] );
 		$this->assertSame( 1080, $result['width'] );
 		$this->assertSame( 1080, $result['height'] );
 		$this->assertSame( 42, $result['seed'] );
 		$this->assertSame( '@cf/black-forest-labs/flux-1-schnell', $result['model'] );
 		$this->assertGreaterThan( 0.0, $result['cost_usd'] );
 		$this->assertGreaterThanOrEqual( 0, $result['latency_ms'] );
 	}
 	/**
 	 * Happy path where Workers AI wraps the image in a JSON envelope with
 	 * base64-encoded bytes under `result.image`. The provider must decode
 	 * and return the raw bytes so the pipeline never has to branch.
 	 */
 	public function test_generate_image_decodes_json_envelope(): void {
 		$this->with_token( 'test-token' );
 		$encoded = base64_encode( self::FAKE_IMAGE_BYTES );
 		$body    = wp_json_encode( [ 'result' => [ 'image' => $encoded ], 'success' => true ] );
 		Functions\when( 'wp_remote_post' )->justReturn( [
 			'body'     => $body,
 			'response' => [ 'code' => 200 ],
 			'headers'  => [ 'content-type' => 'application/json' ],
 		] );
 		Functions\when( 'wp_remote_retrieve_response_code' )->justReturn( 200 );
 		Functions\when( 'wp_remote_retrieve_body' )->justReturn( $body );
 		Functions\when( 'wp_remote_retrieve_header' )->alias(
 			function ( $_response, $name ) {
 				return 'content-type' === strtolower( (string) $name ) ? 'application/json' : '';
 			}
 		);
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$result   = $provider->generate_image( 'a prompt', 600, 600 );
 		$this->assertSame( self::FAKE_IMAGE_BYTES, $result['bytes'] );
 		$this->assertSame( 'image/png', $result['mime_type'] );
 	}
 	/**
 	 * A 401 must NOT retry — auth errors are deterministic and retrying
 	 * burns budget. The provider should throw on the first response.
 	 *
 	 * We can't assert "exactly one HTTP call" without injecting a call
 	 * counter, so we assert that the throw message contains the status.
 	 */
 	public function test_generate_image_fails_loudly_on_401(): void {
 		$this->with_token( 'test-token' );
 		Functions\when( 'wp_remote_post' )->justReturn( [
 			'body'     => '{"errors":[{"message":"bad token"}]}',
 			'response' => [ 'code' => 401 ],
 			'headers'  => [],
 		] );
 		Functions\when( 'wp_remote_retrieve_response_code' )->justReturn( 401 );
 		Functions\when( 'wp_remote_retrieve_body' )->justReturn( '{"errors":[{"message":"bad token"}]}' );
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		try {
 			$provider->generate_image( 'a prompt', 1080, 1080 );
 			$this->fail( 'Expected RuntimeException for HTTP 401.' );
 		} catch ( \RuntimeException $e ) {
 			$this->assertStringContainsString( '401', $e->getMessage() );
 		}
 	}
 	/**
 	 * Response shape must be one of: image/* bytes OR JSON envelope with
 	 * base64 image. Anything else is a contract breach — fail loudly.
 	 */
 	public function test_generate_image_throws_on_unexpected_response_shape(): void {
 		$this->with_token( 'test-token' );
 		Functions\when( 'wp_remote_post' )->justReturn( [
 			'body'     => '<!doctype html><html><body>oops</body></html>',
 			'response' => [ 'code' => 200 ],
 			'headers'  => [ 'content-type' => 'text/html' ],
 		] );
 		Functions\when( 'wp_remote_retrieve_response_code' )->justReturn( 200 );
 		Functions\when( 'wp_remote_retrieve_body' )->justReturn( '<!doctype html><html><body>oops</body></html>' );
 		Functions\when( 'wp_remote_retrieve_header' )->alias(
 			function ( $_response, $name ) {
 				return 'content-type' === strtolower( (string) $name ) ? 'text/html' : '';
 			}
 		);
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$this->expectException( \RuntimeException::class );
 		$provider->generate_image( 'a prompt', 1080, 1080 );
 	}
 	/**
 	 * Cost estimation is positive for in-range dimensions and scales with
 	 * area — a 1080² image costs more than a 600² image on the same model.
 	 */
 	public function test_estimate_cost_scales_with_area(): void {
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$small = $provider->estimate_cost( 600, 600, [ 'model' => 'flux-1-schnell' ] );
 		$large = $provider->estimate_cost( 1080, 1080, [ 'model' => 'flux-1-schnell' ] );
 		$this->assertGreaterThan( 0.0, $small );
 		$this->assertGreaterThan( $small, $large );
 	}
 	/**
 	 * [dev] is meaningfully pricier than [schnell] at the same dimensions —
 	 * the ~4x multiplier is the reason we default to schnell.
 	 */
 	public function test_estimate_cost_dev_more_expensive_than_schnell(): void {
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$schnell = $provider->estimate_cost( 1080, 1080, [ 'model' => 'flux-1-schnell' ] );
 		$dev     = $provider->estimate_cost( 1080, 1080, [ 'model' => 'flux-1-dev' ] );
 		$this->assertGreaterThan( $schnell, $dev );
 	}
 	/**
 	 * validate_credentials_detailed reports 'token_empty' debug tag when
 	 * no token is configured, without making an HTTP call.
 	 */
 	public function test_validate_credentials_reports_missing_token(): void {
 		// Default setUp leaves token empty.
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$result   = $provider->validate_credentials_detailed();
 		$this->assertSame( 'error', $result['status'] );
 		$this->assertSame( 'token_empty', $result['debug'] );
 	}
 	/**
 	 * validate_credentials_detailed returns 'ok' on a 200 from the models
 	 * listing endpoint.
 	 */
 	public function test_validate_credentials_ok_on_200(): void {
 		$this->with_token( 'test-token' );
 		Functions\when( 'wp_remote_get' )->justReturn( [
 			'body'     => '{"result":[{"id":"@cf/black-forest-labs/flux-1-schnell"}]}',
 			'response' => [ 'code' => 200 ],
 		] );
 		Functions\when( 'wp_remote_retrieve_response_code' )->justReturn( 200 );
 		Functions\when( 'wp_remote_retrieve_body' )->justReturn( '{"result":[]}' );
 		$provider = new \PRAutoBlogger_Cloudflare_Image_Provider();
 		$result   = $provider->validate_credentials_detailed();
 		$this->assertSame( 'ok', $result['status'] );
 	}
 }